Asphalt compositions and process for preparing same



United States Patent 3,374,104 ASPHALT COMPOSITIONS AND PROCESS FOR PREPARING SAME Lester A. H. Baum, Cherry Hill, N.J., and Leonard Henschel, Flushing, N.Y., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Oct. 4, 1963, Ser. No. 313,761 5 Claims. (Cl. 106-273) This invention relates to heat-stable thermal asphalts and to a process forproducing them.

In recent years the demand for thermal or cracked asphalts has significantly increased. These asphalt compositions which are widely used such as in the production of insulating building boards and sheathing, as saturant-s for fiber sewer pipe, as binders for coal briquets etc. are generally prepared by the thermal cracking of synthetic tower bottoms from catalytic cracking units such as Thermo-for Catalytic Crackers (TOC); or aromatic gas oils.

The stocks normally used in preparing these thermal asphalts are relatively limited in quantity. Moreover, due to the increased usage of thermal asph alts there is a possibility that the demand for this type of stock may exceed the supply. It would therefore be advantageous to provide for the production of heat-stable thermal asph'alts from stocks other than those presently used.

1 It has now been found that it is-possible to produce a thermal asphalt of good heat stability using fractions which are normally by-products of other processes and are therefore relatively economical sources of supply.

It is an object of the present invention to provide a thermal asphalt of excellent heat stability using economical feed materials.

A further object is to provide a simple and effective process for producing these heat-stable thermal asphalts.

Other objects of the present invention and the advantages thereof will become apparent from the following description.

Broadly stated, the thermal asphalts of the present invention are prepared from resinous pitch materials using controlled distillation procedures.

These resinous pitch materials are highly aromatic pitches or tars. In general, they possess a low-boiling solvent fraction but they are deficient in the high boiling oils which act as plasticizers for the high molecular weight components thereof. More particularly, the resinous pitches used herein may be characterized as possessing the following properties:

Softening point, ring and ball (R&B) F; from about 75 to about 140.

Specific gravity at 77 F.; from about 1.0 to about 1.30.

Conradson carbon, percent; from about 25 to 45.

A preferred pitch is one possessing softening points (R&B) from about 100 to about 130 F, specific grav-i-ties in the range from about 1.10 to about 1. 20 and Conradson carbon values of from about 30 to about 40%.

Particularly desirable resinous pitches of the aforementioned type are those obtained as a by-product from the cracking of light crude and distillate in an ethylene unit to produce ethylene, propylene and heavier hydrocarbons. The pitch obtained from the cracking furnace of the ethylene unit is a solution of hard brittle-type resinous particles in a fairly low boiling solvent fraction. A typical analysis of two suitable resinous pitches is given hereinafter.

The thermal asphal-ts of the invention are produced by blending the resinous pitches with a selected material which functions to plasticize and upgrade the resulting 3,374,104 Patented Mar. 19, 1968 Resinous Pitch Analysis 1 Carbon, percent 93. 5 Hydrogen, percent; 5. 9 Atomic C/H Ratio 1. 32 1. 38 Sulfur, percenL 34 24 Barber Stain Specific G12, 77/77 F H. 1. 178 1.190 Softening Point RdzB, F 122 139 Penetration g./5 scc.:

F I47 Infrared Absorption Index 1. O1 Infrared Transmission Index 1. 0O Conradson Carbon, Percent 31. 6 36. 0 Flash 000, F 390 390 Ash, Percent 06 Viscosity at- 300" F. SFS/cs 20/42 193/411 350 F. SFS/cs 37/79 400 F. SFS/cs 12/26 Solubility in 001 Percent 94. 97 Solubility in 08;, Percent 99. 02

Benzene Insoluble, Percent .IIIIIII L 63 A particularly preferred blending material is a thermal asphalt characterized by the following properties:

Softening point (R&B), about 112 F., Penetration (77 F./100 g./5 sec.), 69, Viscosity at 250 F.=66 centistokes, Specific gravity at 77 H: 1.165.

The resinous pitch materials may comprise, in general, from about 20 to about 80%, preferably about 40 to about 60% by weight of these blends.

The thermal asphalts of this invention are prepared using either of two methods. According to the first method, pitch is distilled, preferably under vacuum to drive off the volatile solvent fraction, and the remaining bottoms fraction admixed with the blending materials. In the second method the pitch is admixed with the blending material and the resulting composition then distilled to remove the low-boiling fraction of the resinous pitch and produce the desired thermal asphalt product.

The distillation conditions employed will vary depending on such factors as the particular nature of the materials used, the relative proportions of pitch and blend ing material, etc.

When employing the first method wherein the resinous pitch alone is distilled, the distillation step is carried out to produce a bottoms product possessing a softening point (R&B) in the range from about 280 to about 300 F. Depending on the characteristics of the pitch, the bottoms may comprise, for example, from about 20 to about 80% of the original feed. In the case where the admixture of resinous pitch and blending material isdistilled, the distillation-is conducted to the extent required to produce a thermal asphalt in the softening point (R&B) range from to 270 F. v

The distillation conditions suitable for producing resinous pitch bottoms and thermal asphalt products possessing the above softening points will be apparent conducted under 'vacuum at temperatures (corrected to 760 mm. of Hg) from about 800 to about 900 F. The thermal asphalts produced according to the present invention are advantageous in that they are produced from an inexpensive pitch material of otherwise limited utility. In addition, the instant thermal asphalts possess to a temperature of 480 F. for a period of 5 hours. At the termination of the test, the sample is removed from the tin box and its weight, softening point and specific gravity determined. From this data the percent weight loss and the softening point increase for the sample are superior heat stability. For example, upon being exposed 5 obtained.

to elevated temperatures these thermal asphalts exhibit The characteristics of the thermal asphalt product and a mlnlmal percent weight loss and only a relatively small the heat hardening test results are given in the followincrease in their softening points. ing Table II.

e following specific embodiments are given to fu It will be noted from these test results that thermal ther Illustrate the Pmsent lnventlollasphalt product obtained from the blends of resinous EXAMPLE 1 pitch and thermal asphalt exhibited percent weight losses of only 10.2%, 8.4% and 5.6% respectively compared The resmous Pltch P E obtamed from the crficiung to percent weight loss of 22.2% incurred by the thermal furnace of ethylene unit is vacuum (2 mm. Hg) dlstllled asphalt containing no resinous pitch to 870 F. corrected vapor temperature and a bottoms fraction comprising about 60% by weight is recovered EXAMPLE 2 and evaluated. The characteristics of the bottoms frac- In h embodiment, the resinous pitch 0% bottoms tlon are reported 111 the followmg Table fraction described in Table I is blended with varying TABLE EJ 5 RESIBOUS PITCH amounts of the 112 F. softening point asphalt fraction y w 0 mm) and the resulting blend is then vacuum distilled under 2 1 SF. (R&B), F 286 mm. (Hg) pressure and at 870 F. corrected vapor tem- Specific gravity 77/77 F 1.219 perature to a desired softening point grade.

Penetration: The characteristics of the resulting thermal asphalt 180/ 1 00/5 1/2 product and the heat hardening test results thereof are 180/ 100-5 2 reported in Table 111.

TABLE III.-VACUUM DIS'IILLATION OF BLENDS 0F RESINOUS PITCH AND THERMAL v ASPHALT Product percent by Wt.:

Thermal Asphalt 75 25 Resinous Pitch 25 50 75 Btms. percent by Wt 79.5 70.0 78.5 09.0 80.1 70.1 s.1 (R&B), F 211 254 190 230 133 220 Sp. Gr., 77/77F 1.219 1.213 1.203 1.209 1.192 1.202 Penetration at- Viscosity at- 300F.SFS/cs 091/1470 340/730 3137/0075 105/223 638/1357 350 F 85/181 555/1202 52/111 242/515 25/53 83/177 400 F 22/47 86/183 15/32 47/100 27/17 20/43 Solubility:

0014, percent 99.0 95.00 95.18 cs5, percent 99.35 90.39 99.37 99.34 Conradson Carbon, percent" 41. 0 45. 9 38. 4 44.2 35. 4 40. 5 Sulfur 0.02 0.01 0. 43 0.54 Heat Hardening (485 F., 5 hr., 200 g.):

Percent Loss 6. 0 6.5 11. 0 4. 4 8.5 3. 8 s2. (R&B), F 233 284 242 257 208 229 8.1. Increase... 22 30 46 21 25 9 Sp. Gm, 77/77F 1.212 1.219 1 20s 1 212 1.203 1.207

Solubility: It will be seen from the foregoing results that the ther- CCl percent 90.11 mal asphalts produced according to this aspect of the in- CS percent 98.20 vention possessed good thermal stability as evidenced by Viscosity at: r5 their low weight losses and the relatively small increases 400 F. SFS/cs. 370/787 0 in their softening points. 450 F 78/195 It will be appreciated that many variations and modi- Flash, COC, F 550 fications can be practiced without departing from the Conradson carbon, percent 50.2 scope or spirit of the present invention.

Heat hardening, (485 F., 5 hr., 200 g.): Having thus described the invention, what we desire to Percent Loss 3.5 secure and claim by Letters Patent is:

S.P. (R&B), F. 296 1. A process for preparing heat-stable thermal asphalts S.P. increase 10 which comprises: Sp. r., 77/77 F. 1.219 blending a resinous pitch material deficient in high- Pen. 180/100/5 1/2 boiling aromatic oils and having a softening point This bottoms fraction of Example 1 is then blended if? g 140 5" a specific with various proportions of 112 F. Softening point g 3 c r m to a out and thermal asphalt fraction as reported in Table II. a S Son at on num er rom about 25 to The characteristics of the resulting product are measured and, in addition, this thermal asphalt is subjected to a maten'al f j at l about by a heat hardening test to determine its heat stability. Welghi of l bolhng aromatlc 0115 and havmg 8 H ha d6, te t softening point (R&B) from about F. to ab r g 8 F.; a specific gravity at 77 F. from about 1.0 7 According to this test, 200 grams of a thermal asphalt to about 1.3; and a Conradson Carbon number from product are placed in a seamless tin box and heated 75' about 20 to about 35%; and

5 distilling the resulting blend to recover a heat-stable thermal asphalt having a softening point (R&B) from about 150 F. to about 270 F.

2. The process of claim 1, wherein said resinous pitch possesses a softening point (R&B) from about 100 to about 130 F.

3. The process of claim 1, wherein said resinous pitch is a bottoms fraction obtained from the cracking furnace of an ethylene unit.

4. The process of claim 1, wherein the resinous pitch is used in proportions ranging from about 20 to about 80% of said blend.

5. The heat-stable thermal asphalt produced by the process of claim 1.

doned.

References Cited UNITED OTHER REFERENCES A.P.C. Application of Robert Horn, Berlin, Germany Ser. No. 245,735, published May 11, 1943, now aban- ALEXANDER, H. BRODMERKEL, Primary Examiner. 15 J. B. EVANS, Assistant Examiner.

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 3,374,101 March 19, 1968 Lester A. H. Baum et a1. It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Columns 3 and 4, Table III, first column, line 13 thereof, for 180/100/5 read 170/100/5; column 4, after line 15 insert the following:

TABLE II.PROPERTIES OF BLENDS OF RESINOUS PITCH BOTTOMS AND THERMAL ASPHALT FRACTION Product Percent Wt.:

Thermal Asphalt 112 F. S. P 100 75 25 Vac. Red. Pitch Btms 0 25 50 S.P. (RdzB), F 112 144 189 230 Sp. Gr., 77l77 F l. 165 1. 183 1. 200 l. 213 Penetration at- 100/5 l8 Viscosity at 250 F. SFS/cs 31/66 206/438 450 F Solubility:

COL, Percent 98. 60 97 47 93 86 94 20 C8,, Percent 99. 70 99. 05 99. 15 98. 88 Flash, COC, F 455 485 500 530 Conradson Carbon, Percent 26. 7 32. 7 38. 8 45. 0 Sulfur, Percent 0. 83 Heat Hardening (480 F., 5 hr., 200 g.):

Percent Loss 22. 2 l0. 2 8. 4 5. 6

S.P. (R&B), F 184 189 224 253 S.P. Increase 72 45 35 23 Sp. Gr., 77/77" F 1. l. 197 l. 209 l. 215 Penetration a.t

Signed and sealed this 22nd day of July 1969.

[SEAL] Attest:

EDWARD M. Frin'rorinn, J R. Attesting Officer.

l/VILLIAM E. SCHUYLER, JR. Commissioner of Patents. 

1. A PROCESS FOR PREPARING HEAT-STABLE THERMAL ASPHALTS WHICH COMPRISES: BLENDING A RESINOUS PITCH MATERIAL DEFICIENT IN HIGHBOILING AROMATIC OILS AND HAVING A SOFTENING POINT (R&B) FROM ABOUT 75*F. TO ABOUT 140*F., A SPECIFIC GRAVITY AT 77*F. FROM ABOUT 1.0 TO ABOUT 1.3 AND A CONRADSON CARBON NUMBER FROM ABOUT 25 TO 45%, WITH A SOLID MATERIAL CONTAINING AT LEAST ABOUT 20% BY WEIGHT OF HIGH BOILING AROMATIC OILS AND HAVING A SOFTENING POINT (R&B) FROM ABOUT 80*F. TO ABOUT 120*F.; A SPECIFIC GRAVITY AT 77*F. FROM ABOUT 1.0 TO ABOUT 1.3; AND A CONRADSON CARBON NUMBER FROM ABOUT 20 TO ABOUT 35*; AND DISTILLING THE RESULTING BLEND TO RECOVER A HEAT-STABLE THERMAL ASPHALT HAVING A SOFTENING POINT (R&B) FROM ABOUT 150*F. TO ABOUT 270*F. 